Year	mm Hg
1980	131.8
1981	131.9
1982	132
1983	132.1
1984	132.2
1985	132.2
1986	132.2
1987	132.3
1988	132.4
1989	132.5
1990	132.6
1991	132.8
1992	132.9
1993	132.9
1994	132.8
1995	132.7
1996	132.6
1997	132.5
1998	132.5
1999	132.4
2000	132.5
2001	132.5
2002	132.6
2003	132.7
2004	132.9
2005	133
2006	133.2
2007	133.4
2008	133.5